Electric stone breaking tool

Abstract

To provide a construction technology of a stone material crushing tool which can avoid complication of a working environment.SOLUTION: An electric stone material crushing tool 101 has: a motor having an output shaft; a motion conversion mechanism which converts rotational output from the output shaft into linear motion; and a crushing part 180 which sandwiches a stone material to crush the stone material through the linear motion by the motion conversion mechanism.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an electric stone breaking tool. [Background technology]

[0002] An example of a stone breaking tool is disclosed in Japanese Utility Model Publication No. 3-27174. This stone breaking tool has a breaking part that clamps and breaks stones, and a hydraulic cylinder for driving the breaking part. Examples of stones include concrete buildings. A relatively strong breaking force is required to break such stones. To ensure a strong breaking force with a hydraulic cylinder, a compressor that supplies pressure fluid to the hydraulic cylinder, a power supply for driving the compressor, a pressure fluid transfer hose connecting the compressor and the hydraulic cylinder, and the like are required, although they are not particularly illustrated in the prior art. For this reason, conventional stone breaking tools have a problem in that the number of necessary equipment, including the auxiliary equipment, is large, and the working environment is easily complicated. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Publication number 3-27174 Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above, an object of the present invention is to provide a technique for constructing a stone breaking tool that can avoid the complication of the working environment. [Means for solving the problem]

[0005] In order to solve the above problems, according to one aspect of the present disclosure, an electric stone breaking tool is configured. The stone crushing tool has a motor with an output shaft, a motion conversion mechanism that converts the rotational output from the output shaft into linear motion, and a crushing unit that clamps and crushes stone via the linear motion produced by the motion conversion mechanism. The "stone material" to be crushed broadly includes, for example, concrete, natural stone, artificial stone, man-made stone, and the like. In addition, "sandwiching and crushing" stone material broadly includes methods such as crushing it with pressure from both sides, cutting it using opposing blades, crushing it with shear force, or a combination of two or more of these. According to the stone crushing tool, the crushing section is electrically driven, which is different from the conventional hydraulic system and eliminates the need for equipment such as a compressor and a hose for transferring pressurized fluid, thereby simplifying and downsizing the working environment.

[0006] In one aspect of the present invention, the motion conversion mechanism is configured as a screw feed mechanism having a screw portion and a nut portion that screws onto the screw portion. Typically, this corresponds to a ball screw shaft mechanism. By adopting a screw feed mechanism, it is possible to efficiently convert large torque into linear motion, while also ensuring the transmission of power for crushing stones and improving the durability of the device.

[0007] In one aspect of the present invention, the output shaft is connected to the threaded portion, and the nut portion is configured to move linearly along the threaded portion when the threaded portion rotates. Regarding "connected to the threaded portion side," this does not preclude the presence of another functional member between the output shaft and the threaded portion. By having the nut portion take on linear motion as the driven member and operate along the threaded portion, the moving part of the movable body can be contained within the size of the threaded portion, making it easier to take measures such as dust prevention without unnecessarily increasing the size of the housing structure.

[0008] In one aspect of the present invention, the crushing unit has a clamping unit that clamps the stone in a predetermined clamping direction, and is configured so that the linear motion direction of the motion conversion mechanism is the clamping direction. Since the linear motion direction of the motion conversion mechanism is the clamping direction, the longitudinal length of the entire stone crushing tool (the direction intersecting the clamping direction) can be made compact. With regard to the "linear motion direction" or "clamping direction," due to the specific mechanical mechanism employed, it is not necessary for the direction or movement to be a geometrically strict linear motion, but it is sufficient if the direction or movement has a linear motion component or an approximately linear motion pattern.

[0009] In one aspect of the present invention, the extending direction of the output shaft is configured to coincide with the clamping direction. The motor is arranged so that the output shaft extends in the clamping direction, which further reduces the longitudinal length of the entire tool.

[0010] In one aspect of the present invention, the crushing unit is configured to have a rotational motion conversion unit that further converts the linear motion produced by the motion conversion mechanism into rotational motion, and to crush the stone material via the rotational motion produced by the rotational motion conversion unit. The rotational motion conversion section and the crushing section may be configured as the same (single) member. Furthermore, the crushing force may be further increased by utilizing a lever effect when the rotational motion is converted by the rotational motion conversion section.

[0011] In one aspect of the present invention, the crushing machine is configured to have a position detection unit that detects a predetermined first position and a predetermined second position in a crushing operation, and a controller that controls the drive of the motor based on the detection result of the position detection unit. Typically, the first position can be set as the work start position, and the second position can be set as the work end position. For example, a stone breaking operation can be started from the first position, and by detecting the second position, the motor can be reversed to return to the initial position. From the viewpoint of ease of detection and certainty, for example, a configuration in which the first position and the second position are set on a linear motion portion of the motion conversion mechanism is preferable. Alternatively, after a predetermined reference position is set, drive control can be performed based on the number of rotations of the motor (history data on the number of rotations the motor has made from the reference position) or the like.

[0012] In one aspect of the present invention, at least one of the first position and the second position is configured to be changeable. Typically, the position can be changed manually by the operator, and can be switched appropriately according to the type of work. For example, the initial position setting can be changed by changing the position of the first position as the work start position, or the work stroke can be changed by changing the relative distance between the first position and the second position as the maximum movable position. In addition, the placement position may be automatically changed depending on the material, size, etc. of the stone.

[0013] According to one aspect of the present invention, a stone crushing detection unit is provided, and the motor is controlled based on the detection result of the stone crushing detection unit. This aspect can be set in combination with the position detection unit described above, or independently. When crushing is detected, the motor can be driven and controlled to return to the initial position. When combined with the position detection unit, for example, the first position can be set as the initial position, the second position as the maximum work position, and in the crushing detection unit, if crushing of the stone is detected before the second position is reached (such as when crushing is completed with a relatively small amount of stone trapped), the initial position return operation can be performed before the second position is reached. This shortens the work stroke and improves work efficiency.

[0014] In addition, the "crushing" in the "crushing detection" includes complete crushing in which the stone is crushed and separated, as well as cases in which the crushed part only penetrates the stone. In addition, the "detection" can be appropriately selected from modes based on fluctuations in parameters such as the motor's drive current and drive voltage, output torque, battery current, battery voltage, torque and axial force in the power transmission path, and modes based on monitoring the operation of the crushing section. When the simplicity and accuracy of the detection mechanism are taken into consideration, it is preferable to detect crushing based on, for example, the torque or axial force in the power transmission path.

[0015] According to one aspect of the present invention, a planetary gear reduction mechanism is interposed between the output shaft and the motion conversion mechanism. By using a planetary gear reduction mechanism, it is possible to make the device configuration for reducing speed compact.

[0016] According to one aspect of the present invention, the tool further includes a handle that is gripped by an operator and a battery that drives the motor, the battery being disposed in the area adjacent to the handle and the handle also serving as the battery guard section. By using a battery for power supply, the working environment can be further simplified. It is preferable that the battery is removable. In addition, by making the handle serve as a battery guard, it is possible to make efficient use of the components.

[0017] According to the present invention, a technique for constructing a stone breaking tool that can avoid the complication of the working environment is provided. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view showing an overall configuration of a stone crushing tool according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a front cross-sectional view of the stone breaking tool. [Diagram 3] FIG. 2 is a partial cross-sectional view showing the configuration of the upper region of the stone breaking tool. [Figure 4] FIG. 2 is a partial cross-sectional view showing the operating state of the stone breaking tool. [Diagram 5] FIG. 2 is a front cross-sectional view showing the operating state of the stone breaking tool. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, a stone crushing tool 101 according to an embodiment will be described with reference to Figs. This stone breaking tool 101 is one example of the "stone breaking tool" according to the present invention.

[0020] Fig. 1 shows the overall configuration of the stone crushing tool 101 in a perspective view. Fig. 2 shows the overall configuration of the stone crushing tool 101 in a front cross-sectional view. Fig. 3 shows a detailed configuration of the upper region of the crushing tool 101 in a partial cross-sectional view. In this embodiment, for convenience of explanation, the width direction of the stone crushing tool 101 (the left-right direction on the paper in Figs. 1 to 3) is defined as a first direction D1, and the up-down direction intersecting with the width direction (the up-down direction on the paper in Figs. 1 to 3) is defined as a second direction D2. The first direction D1 coincides with a stone clamping direction C described later. The "stone material" in this embodiment broadly includes concrete, natural stone, artificial stone, man-made stone, and the like.

[0021] (Exterior configuration) As shown in FIG. 1, the stone breaking tool 101 generally includes a housing 110, a handle 130, and a breaking unit 180 in appearance. (General configuration of housing 110) The housing 110 has a first housing 111 and a second housing 112 .

[0022] (First housing 111) The first housing 111 contains the motor 140 shown in Fig. 3 and a part of the mechanism that receives the output from the motor 140, the details of which will be described later. Adjacent to the first housing 111 is an operation unit 135 that allows an operator to manually input commands to operate the stone crushing tool 101. The operation unit 135 is provided with an operation switch for manual input and a display unit (details are omitted for convenience).

[0023] (Second housing 112) 1, second housing 112 is provided in a lower adjacent region of first housing 111 so as to be connected to first housing 111. Second housing 112 mainly houses therein motion conversion mechanism 160 shown in FIG. 3, the details of which will be described later. The second housing 112 has a second housing base 113 connected to the first housing 111 so as to be immovable relative to the first housing 111, and a second housing movable part 115 configured to be movable relative to the second housing base 113 in the first direction D1. The second housing base portion 113 and the second housing movable portion 115 have integrally formed crushing portion connecting portions 1131 and 1151 for the crushing portion 180 (described below) in their respective end regions.

[0024] (Configuration of handle 130) 1, the handle 130 has a pair of first handles 131 and second handles 132. The first handles 131, 131 are fixedly connected to the first housing 111. The second handles 132, 132 are fixedly connected to a first arm 181 and a second arm 182, respectively, of the crushing unit 180, which will be described later. A battery 146 for power supply is detachably attached to the first housing 111 in a first handle adjacent area 133 between the pair of first handles 131, 131 at the top of the first housing 111.

[0025] (Configuration of the crushing unit 180) The crushing unit 180 is mainly composed of a pair of first and second arms 181 and 182. The upper end regions of the first and second arms 181 and 182 are bifurcated and are assembled to the crushing unit connecting parts 1131 and 1151 of the second housing 112 in a fitting manner. The first and second arms 181 and 182 are connected to the crushing unit connecting parts 1131 and 1151 via first connecting links 1811 and 1821, respectively, so as to be rotatable relative to the crushing unit connecting parts 1131 and 1151. The first arm 181 and the second arm 182 each have stone-holding portions 1813, 1823 with tip protrusions 1815, 1825 and intermediate protrusions 1816, 1826 in their lower tip regions.

[0026] (Definition of "crushing") The "crushing" by the crushing unit 180 includes the manner in which the stone is crushed, cut, crushed by shear force, etc. For example, when the tip convex parts 1815, 1825 or the middle convex parts 1816, 1826 are used, a combined destructive action of cutting or shearing and crushing occurs. Also, when parts other than the tip convex parts 1815, 1825 or the middle convex parts 1816, 1826 are used, a destructive action by crushing occurs. The degree of "crushing" includes complete crushing, such as when the stone material is crushed and separated, as well as a state in which the stone material is not separated but the crushing portion 180 penetrates the stone material.

[0027] (Connection between first arm 181 and second arm 182) As shown in FIG. 1, the first arm 181 and the second arm 182 are rotatably connected to an arm interconnection portion 183 having a pair of plate-shaped members via second connecting links 1812, 1822, respectively, thereby being integrally connected to each other so as to be able to move relative to each other.

[0028] As shown in FIG. 2, which is a front cross-sectional view of the stone crushing tool 101, the first arm 181 and the second arm 182 have engagement portions 1814, 1824 consisting of a recess and a protrusion that engage with each other at the arm interconnection portion 183. As shown in FIG. 2, the pair of second handles 132 are fixedly connected to the first arm 181 and the second arm 182 via second handle fixing portions 1321 and 1322, respectively.

[0029] (Internal structure of stone breaking tool 101) Next, mainly with reference to FIG. 3, the stone breaking tool 101 will be described in detail, focusing on the internal structure in the upper area. (Battery 146) The battery 146 has battery terminals 147 for power supply, and is slidably mounted in a battery mounting section 149 on the main body side provided on the upper part of the first housing 111 by moving substantially in a first direction D1 (in this embodiment, the left direction on the paper in FIG. 3) so as to be freely attached and detached. When mounted, an engagement protrusion 1471 of the battery 146 and an engagement protrusion 1491 of the battery mounting section 149 engage with each other, thereby preventing the battery 146 from accidentally falling off.

[0030] (First housing 111) A first housing 111, which is a component of the housing 110, accommodates a motor 140 having an output shaft 143 and a cooling fan 144, a controller 145 that performs drive control of the motor 140, a planetary gear reduction mechanism 150 that is connected to the output shaft 143 and receives the rotational output of the motor 140, a first gear 151 that receives the rotational output of the planetary gear reduction mechanism 150, and a part of an idling gear 152 that receives the rotation of the first gear 151. The motor 140 is disposed so that the major axis of the output shaft 143 extends in the first direction D1, i.e., is approximately parallel to the first direction D1.

[0031] In this embodiment, a brushless motor is used as the motor 140. A brushless motor does not require a power supply brush, and is relatively small and can provide high output, making it suitable for use in the stone crushing tool 101. In addition, a planetary gear reduction mechanism 150 is used in the power transmission path from the motor 140, making it possible to make the power transmission device configuration compact. The configurations of the motor 140, the planetary gear reduction mechanism 150, and the controller 145 themselves are well known in the art, so a description of their mechanical structures will be omitted, and they will be illustrated diagrammatically in FIG.

[0032] (Motion conversion mechanism 160 in second housing 112) A ball screw mechanism mainly composed of a ball screw shaft 161 and a nut 163 is accommodated in the second housing 112 as the motion conversion mechanism 160. The ball screw shaft 161 is arranged so that its long axis extends in the first direction D1. In other words, the ball screw shaft 161 is arranged so that its long axis is approximately parallel to the first direction D1. The ball screw mechanism having the ball screw shaft 161 and the nut 163 is an example of the "screw feed mechanism" of the present invention. Note that the screw-engagement structure of the ball screw shaft 161 and the nut 163 itself is a well-known technology, so a description of the physical structure is omitted and is illustrated in FIG. 3 as a schematic diagram.

[0033] (Ball screw shaft 161 and load cell 179) A first cap 1611 and a second cap 1612 are provided on both ends of the ball screw shaft 161. A load cell 179 is disposed between the first cap 1611 and the ball screw shaft 161. In addition, a fixing screw 1613 is provided on the second cap 1612.

[0034] The load cell 179 is configured to detect the axial force acting on the ball screw shaft 161 in the first direction D1 and send the detection result to the controller 145. This makes it possible to detect the progress of the stone crushing work. For example, the start timing of the stone crushing work can be detected by an increase in the axial force, and the timing of stone crushing can be detected by a sudden decrease in the axial force. In addition to the axial force itself, the progress of the stone crushing work can be judged preferably by the amount of change in the axial force, the differential or integral value of the amount of change in the axial force, or a combination of these.

[0035] The ball screw shaft 161 is supported by a radial bearing 164 relative to the second housing base 113 so as to be rotatable around the first direction D1. The ball screw shaft 161 is supported by the second housing base 113 via a first thrust bearing 165 and a second thrust bearing 166 in the first direction D1 while receiving an axial force in the first direction D1. The second gear 153 is fixed to an end region of the ball screw shaft 161 via a connecting key 155 disposed in a key groove. The second gear 153 is connected to the above-mentioned idling gear 152. Therefore, the rotation output from the motor 140 is mechanically transmitted to the ball screw shaft 161 via the planetary gear reduction mechanism 150, the first gear 151, the idling gear 152, and the second gear 153, and thus the ball screw shaft 161 is driven to rotate around the first direction D1.

[0036] In this embodiment, the rotation output of the motor 140 is appropriately reduced in speed by the planetary gear reduction mechanism 150, the first gear 151, and the second gear 153, and then transmitted to the ball screw shaft 161. The second gear 153 is fixed to the ball screw shaft 161 in a double-end supported manner at a location sandwiched between radial bearings 164. Since the power transmission points can be supported near both sides, the generation of unnecessary vibrations and couple forces can be effectively suppressed.

[0037] (Nut 163) Furthermore, the nut 163 is screwed onto the ball screw shaft 161 and fixedly connected to the second housing movable part 115. The second housing base 113 and the second housing movable part 115 are connected to be movable relative to each other in the first direction D1 but not rotatable relative to each other around the first direction D1. Therefore, when the ball screw shaft 161 rotates around the first direction D1, the nut 163 is configured to be movable in the first direction D1 by the screwing action with the ball screw shaft 161 while its rotation around the first direction D1 is restricted.

[0038] (Position detection structure for nut 163) A nut interlocking detector 175 is fixedly disposed on the second housing movable part 115 to which the nut 163 is fixedly connected. Meanwhile, a first position detector 177 and a second position detector 178 are disposed along the first direction D1 on the first housing 111 (upper part of the second housing base part 113) in correspondence with the nut interlocking detector 175. The nut interlocking detector 175, the first position detector 177, and the second position detector 178 constitute a nut position detection mechanism 171, which is typically configured by a combination of a magnet and a magnetic sensor. In this embodiment, a magnet is used for the nut interlocking detector 175, and a magnetic sensor is used for the first position detector 177 and the second position detector 178. When the approach of the nut interlocking detector 175 is detected in each of the first position detection unit 177 and the second position detection unit 178, a first position detection signal and a second position detection signal are sent to the controller 145. As will be described later, the first position detection unit 177 corresponds to the initial state (initial position) before the stone crushing tool 101 starts working, and the second position detection unit 178 corresponds to the maximum movable position of the second housing movable part 115 (i.e., the nut 163). Note that such position detection can also be performed, for example, with respect to the motor 140, based on the number of rotations of the motor 140 (history data on how many rotations the motor 140 has made from the reference position) after a predetermined reference position has been set.

[0039] (Connection structure between second housing 112 and crushing unit 180) In the second housing 112, the second housing base 113 has an end region (left end in FIG. 3) that constitutes the crushing unit connection part 1131. The first arm 181 of the crushing unit 180 is rotatably connected to the crushing unit connection part 1131 via a first connection link 1811. Meanwhile, the second housing movable part 115 has an end region (right end in FIG. 2) that constitutes the crushing unit connection part 1151. The second arm 182 of the crushing unit 180 is rotatably connected to the crushing unit connection part 1151 via a first connection link 1821.

[0040] Next, the operation of the stone crushing tool 101 according to this embodiment will be described. (Initial state) 1 to 3 show the initial state before the stone crushing tool 101 starts working. In this state, the worker holds the handle 130 to transport the stone crushing tool 101 and applies the stone clamping parts 1813, 1823 of the crushing unit 180 to the stone W (schematically shown by dotted lines in FIG. 2), which is the work target. FIG. 2 shows the state in which the tip convex parts 1815, 1825 are applied to the planned crushing location of the stone W. Note that the worker can select the middle convex parts 1816, 1826 or other areas of the stone clamping parts 1813, 1823 to apply to the planned crushing location of the stone W according to the work environment or the material and strength of the stone W. In this initial state, the first handle 131 and the second handle 132 are placed in a state in which they extend parallel to each other in the second direction D2.

[0041] 3, in an initial state, the nut 163 is located in a predetermined area (the area adjacent to the ball bearing 164 or the second thrust bearing) of the ball screw shaft 161, and in this state, the nut position detector 175 is placed in a position facing the first position detector 177. Then, the first position detector 177 detects the nut position detector 175 placed in the proximity state, and sends a first position detection signal to the controller 145.

[0042] When an operator manually turns on a drive switch provided on the operation unit 135 shown in FIG. 1, the controller 145 shown in FIG. 3 places the motor 140 in a drive state. Since a brushless motor is adopted as the motor 140, the motor 140 is driven through PWM control by the controller 145. In this embodiment, the drive state of the motor 140 from the initial state is defined as "forward rotation". The rotational motion of the motor 140 is transmitted to the ball screw shaft 161 via the output shaft 143, the planetary gear reduction mechanism 150, the first gear 152, the idling gear 153, and the second gear 153, and the ball screw shaft 161 is driven to rotate around the first direction D1. As a result, the nut 163 screwed onto the ball screw shaft 161 is moved in the first direction D1 without rotation (to the right in FIG. 3). When the nut 163 is moved, the second housing movable part 115 fixedly integrated with the nut 163 is moved relative to the second housing base part 113. Similarly, the nut interlocking detector 175 integrated with the nut 163 is also moved integrally with the nut 163.

[0043] Note that a sealing material 116 (such as a rubber O-ring) is disposed between second housing base 113 and second housing movable part 115, thereby maintaining communication between second housing 112 and the outside. Therefore, even when second housing movable part 115 is moved, dust and the like are effectively prevented from entering second housing 112, or grease and the like is effectively prevented from leaking from second housing 112 to the outside.

[0044] (Second position as maximum movable range: operation of the crushing unit 180) 4, the moving operation of the nut 163 can continue until the nut interlocking detector 175 is detected by the second position detection unit 178. In other words, the second position detection unit 178 defines the maximum movable range of the nut 163. Also, the movable stroke of the nut 163 is defined by the distance between the first position detection unit 177 and the second position detection unit 178 in the first direction D1.

[0045] As described above, the second arm 182 is rotatably connected to the crushing unit connecting part 1151 of the second housing movable part 115 via the first connecting link 1821. Therefore, as shown in Fig. 4, when the nut 163 moves in the first direction D1, the second arm 182 rotates relative to the second housing movable part 115. In addition, the second handle 132 (the second handle 132 on the right side in Fig. 4) fixedly connected to the second arm 182 also rotates.

[0046] (Interlocking of Rotation Between First Arm 181 and Second Arm 182) As described above, the first arm 181 and the second arm 182 are connected at the arm interconnection part 183 via the second connecting links 1812, 1822 and the uneven engagement parts 1814, 1824 (see FIG. 2). As a result, as shown in FIG. 5, when the second arm 182 rotates relative to the second housing movable part 115, the first arm 181 rotates relative to the second housing base part 113 about the first connecting link 1811 in conjunction with the rotation. In addition, the second handle 132 (the second handle 132 on the left side in FIGS. 3 to 5) fixedly connected to the first arm 181 also rotates together with the first arm 181. In other words, the first connecting links 1811, 1821, the second connecting links 1812, 1822, the arm interconnection portion 183, and the uneven engagement portions 1814, 1824 define a rotational motion conversion mechanism 185 for the first arm 181 and the second arm 182, and also define an automatic interlocking mechanism for the rotational motion, and further an automatic interlocking mechanism for the rotational motion of the second handles 132, 132.

[0047] (Torque increase mechanism) Also, as shown in Figures 2 and 5, in this embodiment, the distance between the first connecting links 1811, 1821 and the second connecting links 1812, 1822, and the distance between the second connecting links 1812, 1822 and the stone clamping sections 1813, 1823 (in this embodiment, as an example, stone is crushed using tip convex sections 1815, 1825), and further the distance between the first connecting links 1811, 1821 and the stone clamping sections 1813, 1823 are set so that the rotational motion output by the rotational motion conversion mechanism 185 is greater than the output by the motion conversion mechanism 160, via the action of a lever.

[0048] (Stone crushing work) In this state, as shown in FIG. 5, the first arm 181 and the second arm 182 approach each other in the first direction D1, and the stone clamping portions 1813, 1823 crush the clamped stone W (in this embodiment, the tip convex portions 1815, 1825). In this embodiment, the stone crushing direction C of the first arm 181 and the second arm 182 coincides with the first direction D1. In other words, the stone crushing direction C is configured to be approximately parallel to the first direction D1.

[0049] (Return operation) As shown in FIG. 4, when the approach of the nut interlocking detector 175 is detected by the second position detection unit 178, the controller 145 stops driving the motor 140 (forward rotation) and drives the motor 140 in the reverse direction to move the nut 163 toward the initial position. Then, when the first position detector 177 detects the approach of the nut interlocking detector 175, it is assumed that the motor 140 has returned to the initial position, and the controller 145 stops the reverse drive of the motor 140 (FIGS. 1 to 3 show the initial position). This completes the working stroke of the stone breaking tool 101. In addition, the return operation may be configured to be performed automatically, for example, when the operator stops operating the operation switch (e.g., a trigger) on the operation unit 135 (see FIG. 1) (e.g., by releasing the pressing operation). Alternatively, the automatic return control may not be performed, and the operator may be required to manually perform a return operation. For the manual return operation, for example, a dedicated return switch (return switch) may be provided.

[0050] (Crush detection by load cell 179: working stroke time reduction mechanism) In this embodiment, the load cell 179 is further configured to be able to monitor the axial force (see FIG. 3). Specifically, when performing a stone-crushing operation, a strong axial force acts on the ball screw shaft 161, which is one of the power transmission paths from the motor 140 to the crushing unit 180, in the first direction D1. The load cell 179 disposed between the end of the ball screw shaft 161 and the first cap 1611 detects the axial force and sends it to the controller 145. When the stone is crushed and the axial force acting on the ball screw shaft 161 decreases (suddenly decreases), the controller 145 determines that the stone-crushing operation is completed and stops driving the motor 140 before the second position detection unit 178 detects it. Then, the motor 140 is driven in the reverse direction to return to the initial position. That is, the return to the initial position is completed when the first position detection unit 177 detects the proximity of the nut interlocking detector 175.

[0051] According to this configuration, the completion of the stone breaking operation can be detected through the axial force monitor by the load cell 179 at a stage before the second position detection unit 178 detects the approach of the nut interlocking detector 175 (i.e., at a stage before the full stroke), and the initial position can be returned to. This shortens the working stroke time, which contributes to further improving the working environment. In other words, the load cell 179 constitutes a working stroke time shortening mechanism in the stone breaking tool 101.

[0052] (Work stroke selection (1): Manual selection by the operator) The operator can selectively switch between returning to the initial position when the nut interlocking detector 175 is detected by the second position detection unit 178 described above (working stroke based on maximum movable range), or detecting completion of stone crushing based on the change in axial force by the load cell 179 and returning to the initial position before it is detected by the second position detection unit 178 (shortened working stroke by returning to the initial position at the time stone crushing is completed) via the operating unit 135 described above.

[0053] (Work stroke selection (2): Detection by load cell 179 is the default standard) Alternatively, a configuration may be adopted in which, when the completion of stone crushing is detected based on the change in axial force by the load cell 179, a mode of returning from the detected position to the initial position is standardized (default), and the detection of the nut interlocking detector 175 by the second position detection unit 178 is defined as the "maximum allowable movable range" to prepare for the unlikely event that the detection by the load cell 179 is not working properly. By adopting this configuration, it is possible to shorten the normal working stroke and ensure a safety margin in the event of a detection failure.

[0054] (Change in the location where nut 163 is detected) The above-described first position detector 177 and second position detector 178 can be configured such that the placement locations of one or both of them in first housing 111 can be changed in first direction D1. When the location of first position detector 177 relative to first housing 111 is changed in first direction D1, the first position, which is the initial position, is appropriately changed and adjusted. Furthermore, when the location of second position detector 178 with respect to first housing 111 is changed in first direction D1, the second position as the maximum movable range is appropriately changed and adjusted. As for the method of change, for example, a configuration in which the worker can manually change the placement location, or a configuration in which the location is automatically changed using detection results such as the properties (size, material, hardness, etc.) of the stone being worked on, can be configured.

[0055] For example, when the distance between first position detector 177 and second position detector 178 is changed to be smaller, the stroke distance from the initial position to the maximum movable range can be shortened. Also, for example, by shifting the first position detection unit 177 from the initial position in the movement direction of the nut 163, it becomes possible to make adjustments such as increasing the initial clearance of the stone clamping units 1813, 1823 at the initial position.

[0056] (Advantages of having the ball screw shaft 161 as the driving side and the nut 163 as the driven side) In this embodiment, as described above, in the motion conversion mechanism 160, the ball screw shaft 161 is rotated by the motor 140, and the nut 163 is driven by the ball screw shaft 161 to perform linear motion in the first direction D1. In other words, in the first direction D1, the nut 163, which is the driven member, moves within the range of both ends of the ball screw shaft 161, which is the driving member (moves in an overlapping manner with the ball screw shaft 161 in the first direction D1). Therefore, it is sufficient to design the accommodation space (i.e., the second housing) based on the length dimension (long size) of the ball screw shaft 161, which is a long member, without taking the trouble to create a long space for the driven member. This makes it possible to avoid unnecessarily increasing the width dimension of the stone crushing tool 101 for the movable member, and also makes it easy to take measures against dust for the housing 110.

[0057] (Output shaft 143, ball screw shaft 161, extension direction of stone clamping direction C) In this embodiment, as described above, the extension direction of the output shaft 143 of the motor 140, the extension direction of the ball screw shaft 161 in the motion conversion mechanism 160 (i.e., the moving direction of the nut 163), and the stone gripping direction C by the first arm 181 and the second arm 182 in the crushing unit 180 are all configured to be parallel (see Figs. 2, 3, 5, etc.). Note that the stone gripping direction C is defined as the approximate linear motion direction in the tangential direction of the stone gripping units 1813, 1823 accompanying the relative rotational movement of the first arm 181 and the second arm 182. The parallel arrangement allows the long members and their movements to be concentrated in the width direction of the device, making it possible to make the device configuration more compact than when these components are arranged in a cross-like manner. Note that when the output shaft 143 and the ball screw shaft 161 are arranged in parallel, if they are configured to rotate in opposite directions, for example, this is beneficial in reducing the generation of vibrations and couple forces.

[0058] (Battery 146 protection) In this embodiment, as shown in Fig. 1 etc., the battery 146 is disposed in the first handle adjacent area 133 in the upper part of the first housing 111. This first handle adjacent area 133 is defined as a protective area surrounded by the pair of first handles 131, 131. This suppresses the inadvertent application of external force to the battery 146, and prevents damage to the battery 146 or the battery attachment portion 149 (see Fig. 3). In addition, as shown in Figures 1 and 3, the pair of first handles 131, 131 are open in the sliding installation direction of the battery 146, so that the configuration is such that both the protection of the battery 146 and the ease of sliding installation are achieved.

[0059] According to this embodiment, the above-mentioned configuration and operation mode provide a stone breaking tool 101 that can avoid the complication of the working environment. [Explanation of symbols]

[0060] 101: Stone breaking tools, 110: Housing, 111: 1st housing, 112: second housing, 113: second housing base, 115: second housing movable part, 1131, 1151: Crushing section connection section, 116: Sealing material, 130: Handle, 131: First handle, 132: second handle, 133: First handle proximity area, 135: Operation unit, 1321, 1321: Second handle fixing part 140: motor, 143: output shaft, 144: cooling fan, 145: controller, 146: Battery, 147: battery terminal, 149: Battery mounting section, 1471,1491: Engagement protrusion, 150: Planetary gear reduction mechanism, 151: 1st gear, 152: Idling gear, 153: 2nd gear, 155: Linked key 160: Motion conversion mechanism, 161: Ball screw shaft (threaded part), 1611: 1st cap, 1612: 2nd cap, 1613: Fixing screw, 163: Nut (nut part), 164: Radial bearing, 165: first thrust bearing, 166: second thrust bearing, 171: Nut position detection mechanism, 175: Nut interlocking detector, 177: first position detection unit, 178: second position detection unit, 179: Load cell, 180: Crushing section, 181: first arm, 182: second arm, 1811, 1821: 1st connecting link, 1812, 1822: second connecting link, 1813, 1823: Stone clamping part, 1814, 1824: engagement portion, 1815, 1825: Tip convex part, 1816, 1826: Middle convex part, 183: arm interconnection part, 185: Rotational motion conversion mechanism (handle interlocking mechanism), D1: 1st direction (width direction) D2: Second direction (vertical direction) C: Stone clamping direction W:Stone

Claims

1. a motor having an output shaft; a motion conversion mechanism for converting a rotational output from the output shaft into a linear motion; A crushing unit that crushes stone by clamping it through linear motion by the motion conversion mechanism; a controller having a position detection unit that detects a first position and a second position during a crushing operation, and that controls the drive of the motor based on a detection result of the position detection unit; Stone crushing detection unit and having An electric stone crushing tool characterized in that, when the crushing detection unit detects completion of crushing of the stone before the tool reaches the second position from the first position, the motor is controlled to return to the first position before the tool reaches the second position, and even if the crushing detection unit does not detect completion of crushing of the stone, when the position detection unit detects the second position, the motor is controlled to return to the first position.

2. 2. The electric stone crushing tool according to claim 1, wherein the motion conversion mechanism is configured as a screw feed mechanism having a screw portion and a nut portion screwed into the screw portion.

3. 3. The electric stone breaking tool according to claim 2, wherein the output shaft is connected to the screw portion, and the nut portion is configured to move linearly along the screw portion by rotating the screw portion.

4. 4. An electric stone crushing tool according to claim 1, wherein the crushing unit has a clamping unit that clamps stone in a predetermined clamping direction, and the linear motion direction of the motion conversion mechanism is configured to be the clamping direction.

5. 5. The electric stone breaking tool according to claim 4, wherein the extending direction of the output shaft is configured to coincide with the clamping direction.

6. 6. An electric stone crushing tool according to claim 1, further comprising a rotational motion conversion unit that converts the linear motion generated by the motion conversion mechanism into rotational motion, and the crushing unit crushes the stone through the rotational motion generated by the rotational motion conversion unit.

7. 7. An electric stone breaking tool according to claim 1, characterized in that at least one of the first position and the second position is configured to be changeable.

8. 8. An electric stone breaking tool according to claim 1, wherein a planetary gear reduction mechanism is interposed between the output shaft and the motion conversion mechanism.

9. 9. An electric stone breaking tool according to claim 1, further comprising a handle held by an operator and a battery for driving the motor, the battery being disposed in an area adjacent to the handle, and the handle also serving as the battery guard section.

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